单项选择题 The network 172.12.0.0 needs to be divided into subnets where each subnet has the capacity of 458 IP addresses.What would be the correct subnet mask to accomplish this division keeping the number of subnets at the maximum? （）

多项选择题 A router with a serial interface will be used for an ISDN link.What other function group devices are required to complete the connection to the service provider? （）

单项选择题 A technician at TestKing needs to update the network documentation. One of the tasks includes documenting the name of the IOS image file of each router in the network.Which commands could be used to find this information?（）